Minimally invasive medical techniques have been used to reduce the amount of extraneous tissue which may be damaged during diagnostic or surgical procedures, thereby reducing patient recovery time, discomfort, and deleterious side effects. Traditional forms of minimally invasive surgery include endoscopy. One of the more common forms of endoscopy is laparoscopy, which is minimally invasive inspection or surgery within the abdominal cavity. In traditional laparoscopic surgery, a patient's abdominal cavity is insufflated with gas, and cannula sleeves are passed through small (approximately 12 mm) incisions in the musculature of the patient's abdomen to provide entry ports through which laparoscopic surgical instruments can be passed in a sealed fashion.
The laparoscopic surgical instruments generally include a laparoscope for viewing the surgical field and surgical instruments having end effectors. Typical surgical end effectors include clamps, graspers, scissors, staplers, and needle holders, for example. The surgical instruments are similar to those used in conventional (open) surgery, except that the working end or end effector of each surgical instrument is separated from its handle by an approximately 30 cm. long extension tube, for example, so as to permit the operator to introduce the end effector to the surgical site and to control movement of the end effector relative to the surgical site from outside a patient's body.
In order to provide improved control of the end effector, it may be desirable to control the surgical instrument with teleoperated actuators. The surgeon may operate controls on a console to indirectly manipulate the instrument that is connected to the teleoperated actuators. The surgical instrument is detachably coupled to the teleoperated actuators so that the surgical instrument can be separately sterilized and selected for use as needed instrument for the surgical procedure to be performed. The surgical instrument may be changed during the course of a surgery.
Performing surgery with teleoperated surgical instruments creates new challenges. One challenge is the need to maintain the region adjacent the patient in a sterile condition. However, the motors, sensors, encoders and electrical connections that are necessary to control the surgical instruments typically cannot be sterilized using conventional methods, e.g., steam, heat and pressure or chemicals, because they would be damaged or destroyed in the sterilization process.
Another challenge with teleoperated surgery systems is that a number of connections are required between the surgical instrument and the teleoperated actuator and its controller. Connections are required to transmit the actuator forces, electrical signals, and data. This makes the attachment of the surgical instrument to the teleoperated actuator and its controller complex.
Still another challenge with servo actuated teleoperated surgery systems is that an operating room is not an ideal environment for preparing precision mechanical assemblies.
It is desirable to provide an effective sterile barrier interface between a surgical system's teleoperated actuator and a surgical instrument controlled by the actuator. Although known sterile barrier interfaces have been effective, the need to improve work flow for patient-side surgical personnel and to accommodate advances in teleoperated surgical instrument designs and capabilities requires improved sterile interfaces. Among the required improvements are an ability to quickly, easily, and reliably mount the surgical instrument to the actuator's mechanical drive elements with a known distance between the instrument and the actuator despite the intervening sterile barrier interface (with its associated sterile barrier drape).